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所跟贴 我也给个题目,请高手证明(真或伪): -- Anonymous - (772 Byte) 2002-3-20 周三, 上午10:45 (398 reads)
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文章标题: it's simple (87 reads)      时间: 2002-3-21 周四, 上午12:34

作者:Anonymous罕见奇谈 发贴, 来自 http://www.hjclub.org



The point is:



Suppose {f_n(x)} is a continous function series which converges to f(x) on [0, 1].

Then:



it's NOT necessarily true that the series

{integral of f_n(x) on [0, 1] } converges to integeral of f(x) on [0, 1].



Mathematically, "convengence in uniform" is a sufficient condition

that's generally satisfied.



Unfortunately, the settings in this problem, as you can check,

does not satisfy it.



In mathematics, this "exchange of limit sign with other operators (integral, derivative, etc.)" cannot be applied arbitrarily. One first has to take the burden

to prove that this exchange is VALID. It's usually a big burden.

















作者:Anonymous罕见奇谈 发贴, 来自 http://www.hjclub.org
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